红外迷彩伪装涂料发射率对目标伪装效率的影响

伪装效率是衡量涂料的红外伪装效果的重要指标,它取决于涂料本身的红外发射率、特定的环境背景和气候条件等多种因素。在一种典型的南方草地背景下,随着阳光辐射和昼夜环境温度的变化,研究了不同发射率涂料样品的红外伪装效率;并对不同发射率的样品进行组合,研究比较复杂的红外迷彩伪装目标的伪装效率,在此基础上,讨论了发射率对红外迷彩伪装目标的伪装效率的影响。     

Production and characterization of camouflage poly(ethylene terephthalate) filament yarns during the melt spinning process

The necessity of camouflage in the visible region has been expanded to a broad region of the electromagnetic waves, especially infrared region, due to improving of the night vision cameras. In this investigation, the production of the poly(ethylene terephthalate) (PET) filament yarns with appropriate camouflage properties in both visible and infrared regions of forest areas in the melt spinning process was studied. C.I. Pigment Green 7 and C.I. Disperse Orange 149 with carbon black (CB) particles were used during the melt spinning to obtain the mentioned camouflage properties. The visible and near infrared wavelength reflectances, the mechanical and thermal properties, and the washing and light fastnesses of the camouflage PET filament yarn samples were evaluated. The results showed that the use of the optimum blend content of the mentioned dyes with CB particles during the melt spinning process could make desired camouflage properties in the PET drawn fibers. Moreover, acceptable mechanical and thermal properties accompanied with good to excellent washing and light fastnesses were observed for the optimized camouflage PET filament yarns.     

融合注意力机制与多检测层结构的伪装目标检测

目的 伪装目标是目标检测领域一类重要研究对象,由于目标与背景融合度较高、视觉边缘性较差、特征信息不足,常规目标检测算法容易出现漏警、虚警,且检测精度不高。针对伪装目标检测的难点,基于YOLOv5(you only look once)算法提出了一种基于多检测层与自适应权重的伪装目标检测算法（algorithm for detecting camouflage targets based on multi-detection layers and adaptive weight,MAH-YOLOv5）。方法 在网络预测头部中增加一个非显著目标检测层,提升网络对于像素占比极低、语义信息不足这类目标的感知能力;在特征提取骨干中融合注意力机制,调节卷积网络对特征信息不足目标的权重配比,使其更关注待检测的伪装目标;在网络训练过程中使用多尺度训练策略,进一步提升模型鲁棒性与泛化能力;定义了用于军事目标检测领域的漏警、虚警指标,并提出伪装目标综合检测指数。结果 实验在课题组采集的伪装数据集上进行训练和验证。结果表明,本文方法在自制数据集上的平均精度均值（mean average precision,...     

基于Transformer的跨尺度交互学习伪装目标检测

伪装目标检测(COD)旨在精确且高效地检测出与背景高度相似的伪装物体, 其方法可为物种保护、医学病患检测和军事监测等领域提供助力, 具有较高的实用价值. 近年来, 采用深度学习方法进行伪装目标检测成为一个比较新兴的研究方向. 但现有大多数COD算法都是以卷积神经网络(CNN)作为特征提取网络, 并且在结合多层次特征时, 忽略了特征表示和融合方法对检测性能的影响. 针对基于卷积神经网络的伪装目标检测模型对被检测目标的全局特征提取能力较弱问题, 提出一种基于Transformer的跨尺度交互学习伪装目标检测方法. 该模型首先提出了双分支特征融合模块, 将经过迭代注意力的特征进行融合, 更好地融合高低层特征; 其次引入了多尺度全局上下文信息模块, 充分联系上下文信息增强特征; 最后提出了多通道池化模块, 能够聚焦被检测物体的局部信息, 提高伪装目标检测准确率. 在CHAMELEON、CAMO以及COD10K数据集上的实验结果表明, 与当前主流的伪装物体检测算法相比较, 该方法生成的预测图更加清晰, 伪装目标检测模型能取得更高精度.     

无线传感器网络位置隐私保护技术

对传感器网络位置隐私保护技术的研究现状与进展进行了综述,首先介绍网络模型、攻击模型和性能评价模型.接着,按照路径伪装、陷阱诱导、网络匿名和通信控制这4种策略对现有的研究成果进行了分类,阐述了代表性协议的核心技术.对各协议性能和优缺点的分析比较表明:4种策略都会在一定程度上影响网络的通信和能耗性能:路径伪装策略主要针对逐跳回溯攻击,网络匿名策略主要针对ID分析攻击,陷阱诱导和通信控制策略可以抵御多种类型的攻击.最后,对未来研究方向进行了展望.     

热红外伪装隐身技术探讨

通过热红外探测技术的简单分析,初步探讨了红外热像仪的基本原理,结合热红外伪装隐身的主要技术途径,简单地分析了以表面发射率、热惯量等参数设计实现目标在背景中的热红外伪装隐身的可行性.     

一种基于光子晶体的红外伪装材料

光子晶体作为一种新型人工结构功能材料,基于光子禁带的高反射特性可以实现热红外伪装.选择红外波段透明的常用薄膜材料CdSe、SiO2设计出在中远红外波段具有高反射禁带的光子晶体,利用薄膜光学理论的特征矩阵法计算了反射光谱.通过构造异质结光子晶体,实现了光子带隙的展宽,设计的双周期CdSe/SiO2异质结光子晶体基本上实现了中远红外双波段的高反射,其中在3.14～5.57μm和8.16～13.96 μm的光谱反射率都大于95%,较好地满足了中远红外双波段伪装兼容的要求.倾斜入射时光子晶体的TM波和TE波的反射光谱是不同的,TM波的带隙较之于垂直入射时减小,TE波的带隙较之于垂直入射时增大,TE波在中远红外波段具有高反射的连续区域明显比TM波的大得多.     

Recent progress in two-dimensional nanomaterials of graphene and MXenes for thermal camouflage

Thermal camouflage is one of the most effective ways to guarantee the security and survival of military objects against infrared (IR) detectors. However, with the rapid development of IR detection technology, the IR thermal camouflage of objects and weapons has become more and more difficult, and advanced thermal camouflage materials are urgently needed to meet the demands of warfare. So far, two dimensional (2D) nanomaterials have demonstrated excellent performances with low IR emissivity, optoelectronic tunability, and compatible stealth capabilities. Among them, graphene and MXenes are the most attractive 2D materials used for thermal camouflage applications. Here we present a review of recent progress on the thermal camouflage properties of graphene and Ti₃C₂T_x MXene in the form of composite film, microcapsule and aerogel structures, a summary of current understanding of the working principle of thermal camouflage materials, and current limitations and future opportunities in graphene and Ti₃C₂T_x MXene research and development.     

Multifunctional Metamaterials with Ultrawideband Wave Absorption and Thermal Camouflage

Objects can be identified based on their distinctive scattering signatures in multiple physical areas such as optics, electromagnetics, and thermotics. To ensure comprehensive stealth and camouflage capabilities, antisense devices with multiphysical field coupling are highly desired. Herein, a multifunctional antisense metadevice that achieves stealth in the microwave band while also generating multiple camouflage images from the original object's position during the heat conduction process is proposed and demonstrated. The metadevice combines both antimicrowave detection and camouflage infrared imaging capabilities, resulting in broadband electromagnetic stealth and thermal camouflage effect. Experimental and simulation results confirm the metadevice's ability to achieve these multifunctional capabilities in temperature-dependent cases. The development of such multifunctional devices that span physical fields provides new avenues for the design and preparation of multifunctional structures.